Time-resolved Foerster energy transfer in molecular and polymeric guest-host systems

摘要

Abstract: Sub-picosecond spectroscopy and ultrafast pump-probe experiments spectrally and temporally resolve the Forster energy transfer in blends from larger gap host to the smaller gap guest organic materials. The dynamics of the stimulated emission and photoinduced absorption of the polymer blends indicate that 10 - 20 ps are required for complete energy transfer. The Forster interaction ranges suggested by quantitative measurements of energy transfer rates are compared with the theoretical values as calculated from the spectral overlap. We discuss the effect of the excited state delocalization. The energy transfer dynamics in small organic molecule blends have a longer time scale (1 ns), corresponding to the much longer lifetimes of the organic dyes. !19